What happens to electric car batteries when the car is retired?

Recycling would help offset production impacts of batteries

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Most see electric cars’ key benefit as helping the environment. This goal assumes near-emissions-free transportation, but also the ability to recycle the batteries. Some skeptics have suggested this is a weak link.

There is no question that electric car batteries use large quantities of mined metals, rare earth elements, and toxic materials, and excavating these resources may adversely affect the environment . So if electrified cars aim to be truly green, there is a need to spread their environmental signature as thinly as possible. At the Plug-In 2013 conference in San Diego this week, attendees examined how to get the most out of existing battery materials: first by reusing them, then recycling them. (Learn more about electric cars and alternative fuels.)

John Holmes, head of technology innovation and deployment at San Diego Gas and Electric (SDGE), addressed reusing hybrid batteries. Holmes’ studies of electric car batteries have shown that even when a car battery has only 70 percent of capacity left—too little to serve in a car—that it may have about 10 years of useful life left as storage devices on the grid. Therefore, car batteries may have a role in vast energy storage, as power plants seek to balance electricity generation by day from solar and wind, with consumer demand that spikes in the afternoon and evening.

Beyond that, the battery chemistries in some cars are more conducive to recycling than in others, says Linda Gaines, a systems analyst at Argonne National Laboratory. She has been studying car batteries for years to identify the most effective and profitable ways to recycle.

The nickel-metal hydride batteries found in most conventional hybrids today are very valuable to recycle, because nickel sells for a high price. And any nickel that can be reused in new car batteries reduces the need to mine new nickel for batteries. A few companies around the world are already running commercial nickel-metal-hydride battery recycling centers.

The advanced lithium batteries in most plug-in cars today are more difficult to recycle, in part because automakers use various chemistries, and the several chemical components have different recycling values. Lithium-nickel-manganese-cobalt batteries found in many modern plug-in cars, such as the Nissan Leaf, bring high recycling value because nickel and cobalt are both costly to produce. Cheaper chemistries being planned for future models that promise to help bring electric car prices down are still recyclable. Gaines explains that ongoing developments will provide more efficient ways to extract the elements, eventually making it cost-effective to recycle any chemistry.

The United States has one lithium battery recycling pilot plant under construction in Ohio, though there are active commercial plants in Europe.

The Department of Energy has been working on promoting electric cars for decades. But, in order to maximize the potential environmental benefits, increased attention needs to be given to second-life battery use and recycling.